Abstract: Circuits and methods for suppressing integrated circuit leakage currents are described. Many of these circuits and methods are particularly well-suited for use in dynamic memory circuits. Examples describe the use of power, ground, or both and power and ground source transistors used for generating virtual voltages. An aspect of the invention describes lowering refresh current. An aspect describes reducing the standby current. An aspect of the invention describes lowering leakage resulting from duplicated circuits, such as row decoders and word line drivers. An aspect describes methods of performing early wake-up of source transistors. A number of source transistor control mechanisms are taught. Circuit layouts methods are taught for optimizing integrated circuit layouts using the source transistors.
Type:
Grant
Filed:
September 22, 2006
Date of Patent:
April 19, 2011
Assignee:
Zmos Technology, Inc.
Inventors:
Seung-Moon Yoo, Myung Chan Choi, Young Tae Kim, Sung Ju Son, Sang-Kyun Han, Sun Hyoung Lee
Abstract: Source transistor configurations are described for reducing leakage and delay within integrated circuits. Virtual power and ground nodes are supported with the use of stacked transistor configurations, such as a two transistor stack between a first virtual supply connection and VSS, and a second virtual supply connection and VDD. Gate drives of these stacked transistors are modulated with different voltage levels in response to the operating power mode of the circuit, for example active mode, active-standby mode, and deep power-down mode. Means for driving these source stacks are described. In one embodiment separate virtual nodes are adapted for different types of circuits, such as buffers, row address strobe, and column address strobe. Other techniques, such as directional placement of the transistors is also described.
Type:
Grant
Filed:
July 6, 2006
Date of Patent:
April 27, 2010
Assignee:
Zmos Technology, Inc.
Inventors:
Seung-Moon Yoo, Jae Hoon Yoo, Jeongduk Sohn, Sung Ju Son, Myung Chan Choi, Young Tae Kim, Oh Sang Yoon, Sang-Kyun Han
Abstract: Circuits and methods are described for reducing leakage current and speeding access within dynamic random access memory circuit devices. A number of beneficial aspects are described. A circuit is described for an enhanced sense amplifier utilizing complementary drain transistors coupled to the sense or restore signals and driven by gate voltages which extend outside of the voltage range between VSS and VDD. The drain transistors are self reverse-biased in a standby mode. A method is also described for reducing leaking in non-complementary sense amplifiers by modifying the sense and restore gate voltages. Another aspect is a new negative word line method utilizing stacked pull-down transistors and a multi-step control circuit. In addition a level shifter scheme is described for preventing unwanted current flow between voltage sources while discharging control signal PX.
Abstract: Memory circuits and methods are described providing an interface with high density dynamic memory (DRAM), such 1T1C (1 transistor and 1 capacitor) memory cells, providing full compatibility with static memory (SRAM). The circuitry overcomes the shortcomings with DRAM, such as associated with the restore and refresh operations, which have prevented full utilization of DRAM cores with SRAM compatible devices. The circuit can incorporate a number of inventive aspects, either singly or more preferably in combination, including a pulsed word line structure for limiting the maximum page mode cycle time, an address duration compare function with optional address buffering, and a late write function wherein the write operation commences after the write control signals are disabled.